Thamnasteriamorph

Roniewicz, Ewa, 2011, Early Norian (Triassic) corals from the Northern Calcareous Alps, Austria, and the intra-Norian faunal turnover, Acta Palaeontologica Polonica 56 (2), pp. 401-428 : 422

Genus Thamnasteriamorph a Melnikova, 1971

Type species: Thamnastraea frechi Volz, 1896 , Carnian , Dolomites, Italy .

Thamnasteriamopha aff. frechi ( Volz, 1896)

Fig. 7B.

Material.—A fragment of colony GBA 2009/019/21, with thin sections.

Measurements (in mm): Description.—Colony lamellar. Radial elements (biseptal plates) not numerous, thin, confluent, differentiated into three size orders. Systems irregular. Menianes regularly spaced, symmetrical or alternating, thick, wide, their edges bent upwards and smooth. Internal septal edges thin. Columella styliform, thin. Endotheca of rare, thin, extended dissepiments. In the wall region, synapticulae can be observed. Increase by intercalicular budding, or through corallite division.

Microstructure.—Traces of the microstructure are observable in the septal blades.

Remarks.—The number of septa, and diameters of calices of the Norian form are close to those of the holotype (MGUWr 79sz) of the Carnian Thamnastraea frechi Volz, 1896 (type species of Thamnasteriamorpha ). However, the coral from the Dachstein differs from the type in possessing a thin columella and menianes that are not densely arranged (compare the Measurements above). The state of preservation does not allow for a more detailed description of the characters of the Norian coral.

Stratigraphic and geographic range.— Austria: Northern Calcareous Alps, Dachstein Plateau, north of Feisterscharte, lower Norian, Epigondolella quadrata conodont Zone.